It said the future of PR, and its intrinsic value, was that it was capable of outsmarting rival disciplines by using innovation and that this was driven by clients, shareholders and staff.

The project identified a "chasm" opening up between business models used by traditional agencies and the demands of modern clients, and said that the most innovative agencies were adapting to those needs.

Size is no bar to success either, with the smallest firms able to compete with the largest, and the white paper argued that better measurement systems were "fundamental" to innovation.

The core services offered by the modern agency include storytelling, creative and content, as well as paid, earned and shared media as they shift away from traditional media.

But the project also identified threats to the future agency model, such as the shift to 24/7 working and the cost of infrastructure.

Seventeen agency leaders, including Stephen Waddington, partner and chief engagement officer at Ketchum, and Sarah Hall, managing director of Sarah Hall Consulting, contributed to the findings of the FuturePRoof project.

Waddington said: "The project set out with a bold and simple ambition: to characterise a cross-section of agencies that make up the modern public relations business. The result is a must read for anyone working in the public relations agency business."

The white paper, called ‘Exploring the Public Relations Agency’, consists of 15 essays exploring different areas of agency innovation and is available to download free.